钩藤总生物碱对D-半乳糖诱导的内皮细胞衰老的干预

目的探讨钩藤总生物碱保护血管内皮细胞、抑制血管内皮细胞衰老的作用。方法采用D-半乳糖诱导的大鼠主动脉内皮细胞建立衰老模型,扫描电镜技术观察衰老血管内皮细胞的形态,β-半乳糖苷酶染色法测定衰老血管内皮细胞发生率以间接反映β-半乳糖苷酶表达,PCR-ELISA法测定衰老血管内皮细胞端粒酶活性。结果钩藤总生物碱可以改善血管内皮细胞形态、降低内皮细胞中β-半乳糖苷酶表达和端粒酶活性相对表达量(P<0.05)。结论钩藤总生物碱具有抑制内皮细胞衰老、保护血管内皮的效用。     

长期吸烟加速肺组织细胞端粒长度缩短诱导衰老发生的研究

目的:观察长期吸烟对肺组织细胞衰老影响和端粒长度的变化。方法:将Wistar大鼠30只分为对照组和吸烟组,对照组15只,吸烟组15只,给予被动吸烟刺激6个月,利用荧光定量PCR的方法检测组织端粒的长度,western blot检测衰老相关的指标,Flow-Fish的方法检测香烟烟雾提取物(CSE)对于HPAEC(HPAEC)端粒长度的影响,免疫荧光法检测细胞中P53的表达同时利用β-半乳糖苷酶(SA-β-gal)衰老染色进行辅助验证。结果:荧光定量PCR方法检测吸烟组端粒相对T/S比率平均为(8.99±1.70),正常组端粒的相对T/S比率平均为(17.3±0.65),吸烟组端粒长度明显短于正常组(P<0.01),western blot检测组织中衰老相关蛋白P53,P21的表达量较对照组明显升高;免疫荧光表现可见加入CSE刺激的HPAEC中P53表达升高,Flow-fish检测CSE刺激HPAEC时间0h、12h、24h、48h及72h端粒相对长度为N、0.89N、0.723N、0.51N及0.48N。结论:长期吸烟可以诱导肺组织和HPAEC发生衰老表现为端粒长度缩短。     

C1q/TNF相关蛋白3减轻氧化应激诱导的间充质干细胞衰老

目的建立间充质干细胞(MSCs)衰老模型,探讨C1q/TNF相关蛋白3(CTRP3)对衰老MSCs的作用并初步探讨机制。方法用过氧化氢(H_2O_2)诱导小鼠MSCs衰老,CCK8实验和β-半乳糖苷酶染色验证模型的建立。外源性给予CTRP3处理MSCs 24 h,CCK8实验检测增殖活性,β-半乳糖苷酶染色检测MSCs衰老,分化诱导实验检测MSCs分化能力,Western blotting法检测MSCs凋亡。RT-PCR检测MSCs中衰老相关基因P16、P21以及抗衰老基因SIRT1的mRNA表达变化。采用GraphPad Prism 6进行统计分析。组间比较采用方差分析或LSD两两比较。结果 H_2O_2可抑制MSCs的增殖活性,且呈浓度依赖性。与正常对照组相比,200μmol/L H_2O_2作用4 h,细胞立体感消失,细胞形态不规则;CCK8染色结果显示细胞增殖活性显著下降;β-半乳糖苷酶阳性细胞百分比显著升高。继续CTRP3处理24 h后,衰老MSCs增殖和分化能力增强。Western blotting结果表明CTRP3可显著减低衰老MSCs的凋亡。RT-PCR检测发现CTRP3上调MSCs抗衰老基因SIRT1 mRNA表达,并且下调衰老相关基因P16、P21 mRNA的表达。结论 CTRP3可抑制MSCs衰老,SIRT1基因表达水平上调,及P16、P21基因表达水平下调可能是其重要机制。     

端粒酶在整倍体与非整倍体细胞中的表达差异

目的探讨端粒酶在HCT116整倍体细胞与非整倍体细胞中的表达差异及其端粒酶抑制剂,叠氮脱氧胸苷(AZT)对整倍体和非整倍体细胞h TERT基因表达及端粒酶活性变化的影响。方法取HCT116细胞加入盐酸强力霉素16 h后撤药,设为非整倍体组;另取HCT116细胞不作任何处理,称为整倍体组;在撤药后第11天,分别采用0、100、250μmol/L的AZT处理两组细胞72 h,分别设立空白对照组和AZT处理组。采用染色体滴定法对两组细胞的染色体进行计数。采用Western blot检测撤药后第3、6、11天MAD2L1蛋白的表达。运用RT-PCR法检测整倍体组、非整倍体组及AZT处理组h TERT基因的表达,端粒酶活性试剂盒检测端粒酶活性。结果盐酸强力霉素可以通过破坏MAD2L1诱导非整倍体,非整倍体率可达到78%;整倍体组和非整倍体组细胞在第6、8、11天h TERT mRNA基因的表达量分别为(1︰1.19±0.05、1︰1.21±0.02、1︰1.46±0.04),端粒酶活性分别为(2.87±0.01︰3.14±0.10、2.89±0.01︰3.25±0.03、2.79±0.03︰4.26±0.15),非整倍体组细胞的h TERT mRNA基因的表达量、端粒酶活性明显高于整倍体,两组细胞在第6、8、11天比较具有统计学差异(P0.05);整倍体组细胞在100、250μmol/L处的h TERT mRNA基因下降率分别为5%、32%,端粒酶活性下降率为14.69%、25.40%;非整倍体组细胞在100、250μmol/L处的h TERT mRNA基因下降率分别为38.46%、51.28%,端粒酶活性下降率为17.00%、74.59%。两组细胞h TERT mRNA基因下降率在100、250μmol/L处具有统计学差异(P0.05)。两组细胞端粒酶活性下降率在250μmol/L处具有统计学差异(P0.05)。结论盐酸强力霉素可以诱导非整倍体形成,非整倍体细胞的端粒酶活性及h TERT基因表达高于整倍体细胞,AZT可以抑制整倍体细胞和非整倍体细胞h TERT基因的表达及端粒酶活性,非整倍体细胞对AZT更敏感。     

脑蛋白水解物-Ⅰ防治C57小鼠脑衰老的作用机制

目的研究脑蛋白水解物(CH)-Ⅰ延缓D-半乳糖(D-gal)致C57小鼠衰老的作用机制。方法C57/BL6N小鼠随机分为对照组、模型组、CH-Ⅰ低剂量组和CH-Ⅰ高剂量组,皮下注射D-gal以诱导衰老模型,给药组腹腔注射CH-Ⅰ。Morris水迷宫实验检测小鼠的学习和记忆能力,苏木素-伊红(HE)染色观察神经元的形态结构,Western印迹检测脑源性神经营养因子(BDNF)、信号传感器和转录激活因子(STAT)3/磷酸化(p)-STAT3和端粒酶逆转录酶(TERT)的表达,PCR-酶联免疫吸附试验(ELISA)检测端粒酶活性的表达。结果与对照组相比,模型组学习记忆能力显著下降(P<0.01),海马神经元损伤明显增加(P<0.01),端粒酶活性明显降低(P<0.01),BDNF、TERT和p-STAT3表达水平下降(P<0.01)。而给予不同浓度的CH-Ⅰ预处理后,衰老小鼠的学习记忆能力障碍得到改善(P<0.05),海马神经元损伤显著下降(P<0.05),并且CH-Ⅰ低、高浓度均可以显著提高小鼠海马组织的端粒酶活性(P<0.05),上调BDNF、端粒酶催化亚基TERT和调控因子STAT3的蛋白表达(P<0.05)。结论CH-Ⅰ可以通过提高端粒酶活性的表达从而减少D-gal衰老小鼠海马组织的衰老损伤。     

阿司匹林抗高糖诱导的内皮细胞衰老的作用

目的 探讨阿司匹林是否具有抗高糖诱导的内皮细胞衰老的作用及其机制。方法 人脐静脉内皮细胞（HUVEC）分别于正常糖浓度培养液 （5.5 mmol/L）、高糖培养液和高糖（33 mmol/L）＋阿司匹林（0.01、0.1、1及3 mmol/L）培养液中培养48 h,观察细胞形态、采用β-半乳糖苷酶染色鉴定衰老细胞,PCR-ELISA检测端粒酶活性,流式细胞仪检测细胞周期和细胞内活性氧水平。结果 高糖培养液作用HUVEC 48 h后,细胞呈现衰老状态,β-半乳糖苷酶染色阳性细胞数明显增加,端粒酶活性明显减低,细胞周期停滞于G0/G1期,S期显著减少,细胞内活性氧水平显著增加。0.01、0.1和1 mmol/L阿司匹林作用后细胞形态改善,β-半乳糖苷酶染色阳性细胞数显著减少,端粒酶活性增强,S期细胞显著增加,细胞内活性氧水平降低（P<0.05）。而3 mmol/L阿司匹林作用后与高糖组相比差异无显著性。结论 高糖环境下阿司匹林（0.01、0.1和1 mmol/L）具有抗内皮细胞衰老的作用,其作用机制可能与氧化应激有关。     

叠氮胸苷对胃癌端粒酶活性及细胞增殖的影响

目的探讨反转录酶抑制剂叠氮胸苷对端粒酶活性的影响及抑制端粒酶活性以控制胃癌生长的可能性。方法采用端粒重复片段扩增法（ｔｅｌｏｍｅｒｅｒｅｐｅａｔａｍｐｌｉｆｉｃａｔｉｏｎｐｒｏｔｏｃｏｌ,ＴＲＡＰ）和流式细胞术等检测胃癌细胞经叠氮胸苷处理前后的端粒酶活性和细胞增殖能力。结果经叠氮胸苷处理后,培养的胃癌细胞端粒酶活性较未处理组降低８４．１％,出现衰老形态的细胞,处理１４和２１天后生长抑制率分别为５９．３％和８０．９％,细胞存活分数明显降低,分别为０．５４和０．３３,并对细胞周期具有一定影响。结论叠氮胸苷可明显抑制胃癌细胞端粒酶活性,诱导细胞衰老和增殖能力的降低,临床上应用端粒酶抑制剂限制端粒扩充治疗胃癌可能具有广阔的前景。     

利用高内涵筛选显微镜技术评估培养的间充质干细胞衰老程度

目的探讨利用高内涵筛选显微镜技术来评估培养的间充质干细胞(MSCs)衰老程度的可能性。方法采用高内涵筛选显微镜技术,对4个连续培养的骨髓MSCs样本的细胞形态、面积变化进行分析,同时检测端粒长度和衰老相关的β-半乳糖苷酶(SA-β-gal)活性,分析数据的相关性。结果 p2、p4、p6、p8细胞大小呈逐步显著增大趋势(均P0.05);端粒长度呈逐步显著缩短趋势(均P0.05);SA-β-gal活性呈逐步显著增加趋势(均P0.05)。结论利用无创的高内涵筛选显微镜技术计算细胞面积可作为衰老检测的一个显著指标。     

十两茶提取物抗氧化型低密度脂蛋白诱导的内皮细胞衰老机制研究

目的：探讨十两茶提取物对氧化型低密度脂蛋白（ox-LDL）诱导衰老细胞模型的影响及其可能的机制。方法将人脐静脉内皮细胞（HUVECs）株于含有10%牛血清的DMEM培养液中培养,使用ox-LDL孵育建立衰老细胞模型,用β?半乳糖苷酶染色法评价内皮细胞的衰老状态,分别予以不同剂量十两茶提取物及辛伐他汀预处理,检测培养液中活性氧（ROS）、非对称二甲基精氨酸（ADMA）、二甲基精氨酸二甲胺水解酶（DDAH）以及端粒酶活性水平。结果 ox-LDL诱导的内皮细胞衰老模型中β?半乳糖苷酶染色阳性的细胞数量显著增加,细胞内ROS水平、ADMA水平增强,DDAH和端粒酶活性降低,而十两茶提取物预处理可明显抑制这一过程（P＜0.05）。结论十两茶提取物在ox-LDL诱导的内皮细胞衰老进程中起抑制作用,其机制可能与降低细胞内ROS、ADMA水平以及提高DDAH水平和端粒酶活性有关。     

硫化氢通过SIRT1抗内皮细胞衰老

目的探讨外源性硫化氢在人脐静脉内皮细胞(HUVEC)衰老中的作用及分子机制。方法用25μmol/L H2O2诱导HUVEC衰老,通过检测β-半乳糖苷酶计算细胞衰老率。检测不同浓度(15、30、60及120μmol/L)的硫氢化钠作用下内皮细胞衰老标志物β-半乳糖苷酶的表达,Western blot分析沉默信息调节因子1(SIRT1)蛋白的表达。结果 HUVEC经25μmol/L H2O2处理1 h后,β-半乳糖苷酶阳性细胞率为12.2%±1.30%;经60μmol/L硫氢化钠干预48 h后,β-半乳糖苷酶阳性细胞率显著降低,为4.6%±1.14%,两组相比差异显著(P<0.05);与对照组比较,60μmol/L硫氢化钠干预48 h后SIRT1蛋白表达显著上调(P<0.05),而用SIRT1抑制剂(NAM)可减弱硫氢化钠此作用(β-半乳糖苷酶阳性细胞率为12.0%±1.58%)。结论硫化氢能通过上调SIRT1表达抵抗H2O2诱导HUVEC衰老。     

Homocysteine accelerates senescence and reduces proliferation of endothelial progenitor cells

Our previous studies showed that homocysteine (Hcy) reduces endothelial progenitor cell (EPC) numbers and impairs functional activity. However, the mechanisms by which Hcy reduces EPCs numbers and activity remain to be determined. Recent studies have demonstrated that reduced EPCs numbers and activity was associated with EPCs senescence which involved telomerase activity. Therefore, we investigated whether Hcy accelerates the onset of EPCs senescence through telomerase inactivation, leading to cellular dysfunction. EPCs were isolated from peripheral blood and characterized. After ex vivo cultivation, EPCs became senescent as determined by acidic beta-galactosidase staining. Hcy dose-dependently accelerated the onset of EPCs senescence in culture. Moreover, Hcy decreased proliferation of EPCs as assessed by BrdU incorporation assay and colony-forming capacity. To get further insights into the underlying mechanisms of these effects induced by Hcy, we measured telomerase activity and determined the phosphorylation of Akt by using western blot. Hcy significantly diminished telomerase activity and Akt phosphorylation. Taken together, the results of the present study demonstrated that Hcy accelerated the onset of EPCs senescence, leading to cellular dysfunction. The effect of Hcy might be dependent on telomerase inactivation, and Akt dephosphorylation also appeared to play a major role. In addition, atorvastatin had a preventative effect against Hcy-induced EPCs senescence.     

长春新碱对INS-1细胞hTERT、Sp1、c-myc基因表达影响的研究

目的观察抗肿瘤药物长春新碱（Vincristine,VCR）对大鼠胰岛B细胞瘤株INS-1细胞增殖和侵袭的抑制作用和hTERT、Sp1、c-myc表达的影响及其意义,探讨胰岛B细胞瘤的发病机制。方法 INS-1分为对照组（不加VCR）和实验组（加入浓度分别为0.008 mg/mL、0.04 mg/mL、0.2 mg/mL、1 mg/mL的VCR）。两组培养24 h后,用MTT比色法检测INS-1细胞的增殖抑制率;用Transwell侵袭试验检测INS-1细胞的侵袭力;RT-PCR检测各组细胞中hTERT、Sp1、c-myc基因的表达。结果实验组抑制率明显高于对照组（P〈0.05）;且随着VCR浓度的增加,INS-1细胞生长抑制率逐渐增加（P〈0.05）;Transwell小室培养细胞24 h后,实验组侵袭到下层膜的细胞数为（63.26±5.12）个,对照组为（150.65±4.02）个（P〈0.01）;与对照组比较,随着时间的延长,实验组的hTERT、Sp1、c-myc mRNA基因在INS-1细胞的表达也逐渐减弱（P均〈0.05）。结论 VCR能抑制INS-1细胞增殖和侵袭,可能通过抑制Sp1、c-myc和hTERT表达,从而抑制INS-1的端粒酶活性,进而抑制细胞增殖和降低侵袭能力。     

Endothelial progenitor cell senescence is accelerated in both experimental hypertensive rats and patients with essential hypertension

OBJECTIVES: Recent studies have revealed an association between coronary risk factors and both the number and function of bone marrow-derived endothelial progenitor cells (EPCs). Although hypertension is an important coronary risk factor, the influence to the EPCs is not fully understood. We investigated the effect of hypertension on EPC senescence. METHODS: Experimental study We investigated the number and senescence of EPCs in spontaneously hypertensive rats (SHR/Izm) and deoxycorticosterone acetate (DOCA)-salt hypertensive rats. EPCs were isolated from peripheral blood of rats and were characterized. EPC senescence was detected by acidic beta-galactosidase staining. In addition, we measured the telomerase activity using polymerase chain reaction-enzyme-linked immunosorbent assay. CLINICAL STUDY: EPCs were isolated from peripheral blood samples in 37 patients with essential hypertension. After ex-vivo cultivation, we detected senescence and measured the telomerase activity. The total severity index of hypertension-induced organ damage was calculated by the summation of each severity index in the classification of hypertension severity by Tokyo University (1984). RESULTS: Experimental study The EPC senescence in SHR/Izm and DOCA-salt hypertensive rats was significantly increased compared with that of control rats. The telomerase activities in SHR/Izm and DOCA-salt hypertensive sensitive rats were also significantly lowered compared with those of control rats. Clinical study Compared with the control group, EPCs from hypertensive patients showed accelerated senescence and also showed reduced telomerase activity. In hypertensive patients, the degree of hypertension-induced organ damage was negatively correlated with telomerase activity, and was positively correlated with EPC senescence. CONCLUSIONS: EPC senescence is accelerated in both experimental hypertensive rats and patients with essential hypertension, which may be related to telomerase inactivation. The hypertension-induced EPC senescence may affect the process of vascular remodeling.     

C反应蛋白诱导外周血内皮祖细胞衰老及非诺贝特的保护作用

目的研究非诺贝特对C反应蛋白诱导的外周血内皮祖细胞衰老的影响及可能机制。方法随机将分离培养的内皮祖细胞分为4组:①对照组;②C反应蛋白各浓度组(1.0、2.5、5.0 mg/L);③C反应蛋白(5.0 mg/L)+非诺贝特(10.0μmol/L)组;④非诺贝特组(10.0μmol/L)。加入不同浓度的C反应蛋白干预,或预先加入非诺贝特作用4 h,再加入5 mg/L C反应蛋白,培养7天后行SA-β-半乳糖苷酶染色,检测细胞衰老并计数每组衰老细胞数。逆转录-聚合酶链反应检测人端粒酶逆转录酶mRNA表达。免疫印迹杂交法半定量测定内皮型一氧化氮合酶蛋白表达。结果 (1)不同浓度的C反应蛋白与内皮祖细胞培养后,C反应蛋白促进内皮祖细胞的衰老,且C反应蛋白对内皮祖细胞衰老的影响随着C反应蛋白浓度的增加而增加,5 mg/L C反应蛋白组对内皮祖细胞衰老的影响最显著(P<0.01)。加入10μmol/L非诺贝特后能减少C反应蛋白诱导的衰老细胞数量(P<0.01)。(2)C反应蛋白作用内皮祖细胞后人端粒酶逆转录酶mRNA表达随着C反应蛋白作用浓度的增加而下降,加入非诺贝特10μmol/L后可以明显逆转C反应蛋白诱导的人端粒酶逆转录酶mRNA表达下调(P<0.01)。(3)C反应蛋白抑制内皮型一氧化氮合酶蛋白表达,但在加入10μmol/L非诺贝特后能明显上调内皮型一氧化氮合酶蛋白表达(P<0.01)。结论 (1)C反应蛋白削弱内皮祖细胞的内皮型一氧化氮合酶表达,引起人端粒酶逆转录酶的逆转录下降,从而使端粒酶活性下降,最后加速内皮祖细胞的衰老,从而影响内皮祖细胞的功能。(2)非诺贝特活化人端粒酶逆转录酶,抑制C反应蛋白诱导的细胞衰老,可能与内皮型一氧化氮合酶表达上调有关,从而起到保护内皮祖细胞的作用。     

Telomere and telomerase in the initial stage of immortalization of esophageal epithelial cell

AIM: To search for the biomarker of cellular immortalization, the telomere length, telomerase activity and its subunits in cultured epithelial cells of human fetal esophagus in the process of immortalization. METHODS: The transgenic cell line of human fetal esophageal epithelium (SHEE) was established with E(6)E(7) genes of human papillomavirus (HPV) type 18 in our laboratory. Morphological phenotype of cultured SHEE cells from the 6th to 30th passages, was examined by phase contrast microscopy, the telomere length was assayed by Southern blot method, and the activity of telomerase was analyzed by telomeric repeat amplification protocol (TRAP). Expressions of subunits of telomerase, hTR and hTERT, were assessed by RT-PCR. DNA content in cell cycle was detected by flow cytometry. The cell apoptosis was examined by electron microscopy (EM) and TUNEL label. RESULTS: SHEE cells from the 6th to 10th passages showed cellular proliferation with a good differentiation. From the 12th to the 16th passages, many senescent and apoptotic cells appeared, and the telomere length sharply shortened from 23kb to 17kb without expression of hTERT and telomerase activity. At the 20th passage, SHEE cells overcame the senescence and apoptosis and restored their proliferative activity with expression of telomerase and hTERT at low levels, but the telomere length shortened continuously to the lowest of 3kb. After the 30th passage cells proliferation was restored by increment of cells at S and G2M phase in the cell cycle and telomerase activity expressed at high levels and with maintenance of telomere length. CONCLUSION: At the early stage of SHEE cells, telomeres are shortened without expression of telomerase and hTERT causing cellular senescence and cell death. From the 20th to the 30th passages, the activation of telomerase and maintenance of telomere length show a progressive process for immortalization of esophageal epithelial cells. The expression of telomerase may constitute a biomarker for detection of immortalization of cells.